Whenever I tout the magical abilities of acids for skin, I'm met with a degree of horror. "Acids on your skin?" *shriek*. I'm talking specifically about AHAs and BHAs, which, used in low concentrations, help to gently lift away the glue that holds dead skin in place to reveal the fresh, healthy skin beneath. BHAs can help unplug the goop clogging pores and AHAs can re-texturise for a smooth, glowy finish – all while causing far less inflammation than a scratchy apricot kernel ever could. And yet many are still reluctant to use them. To them, I say, fair enough. While AHAs and BHAs work seamlessly for lots of people, it's true that they can cause slight redness and irritation for some, particularly if your skin is quite sensitive.
However, there's a new kid on the block, in the form of PHA (Polyhydroxy acid), which promises to do all of the above but much more gently, meaning it's perfect for those with sensitive skin. "Polyhydroxy acids are very similar to traditional AHAs," says Daniel Issacs, formulation and development director at skincare brand Medik8. "Both help to speed up cell turnover and reveal a brighter and smoother complexion." However, "PHAs are much larger in size, meaning they can't penetrate as deeply as AHAs and BHAs," he says. "They can do everything an AHA can do, but without irritation and therefore they're great for people with sensitive skin," agrees clinical aesthetician Pamela Marshall.
And, that's not all. Unlike AHAs and BHAs, which can cause skin to feel dry, PHAs are excellent at hydrating, as they attract water to our skin, leaving it feeling more comfortable. Added to that, PHAs are natural antioxidants, which means they can neutralise damage caused by pollution (such as premature ageing and dull-looking skin) before it occurs, explains Isaacs. And, like AHAs, they can help with dark spots, too, by increasing cell turnover to fade pigmentation quicker. If it sounds too good to be true, there is one catch: PHAs are recently out of patent – skincare brand NeoStrata held the rights to the ingredient until a short while ago – which means that, right now, it's expensive to use and license. But, expect to see a whole host of PHA-filled products rolling out across the high street and into your skincare soon.
6 of the best
The best at brightening: Medik8 White Balance Cleanse
This is a powder cleanser that you add water to and lather up into a paste. The slightly granular formula is created from micro-fine particles in bamboo, which provides a light amount of manual exfoliation, while the PHA (which in this case is Gluconolactone), kickstarts cell renewal and gives skin a bit more moisture. It also contains patented Oxyresveratrol, which helps to lighten the appearance of pigmentation over time. It leaves skin feeling clean, without feeling dried out or tight. Use a teaspoon amount mixed with water and apply across your face avoiding your eyes.
The Best if you're an inbetweener: Zelens PHA+ Bio-Peel Resurfacing facial pads
A blend of AHAs and BHA, and diluted with PHA, this is one to go for if you find other liquid exfoliators too drying, but like the exfoliation that AHAs and BHAs provide. It's also a good option if you don't get on well with glycolic acid (the most common AHA), as this contains lactic and citric acid instead. Though it tingled a little, it worked well on my mildly sensitive skin and left it looking very fresh and smooth. Also the pre-soaked pads are nice and easy to use. If you're fairly sensitive, I'd stick to using this one a fortnight or as often as your skin needs.
THE BEST ON THE HIGH STREET: GLOSSIER EXFOLIATING SKIN PERFECTOR
This is also a blend of all three acids: AHA, BHA and PHA. If you don't really suffer from sensitivity and you're comfortable using chemical exfoliants but find they dry your skin out, you may like this. It was too much for my skin – it has that strong tingly feeling that will put sensitive skins off – however, it does effectively resurface skin leaving it smooth, bright and crucially, hydrated. It's best used just once a week, though.
The best for protecting against pollution: Exuviance Vespera Bionic Serum
Like Zelens, the science behind this is reflected in the price. And, like Zelens, this is a blend of AHAs and PHAs – however the Alpha Hydroxy Acid used (mandelic acid) is much gentler than the more common AHAs, so is less likely to cause skin sensitivity. And though it has quite a strong, zesty orange scent – that normally gets my alarm bells ringing on the skin-irritation front (and is a sensory addition, rather than a necessary skin-perking one) – it felt pleasingly gentle on my skin. Alongside two PHAs (gluconolactone and lactobionic acid), it's supercharged on the antioxidants front, with vitamins A, C and E, making it excellent at protecting against pollution and environmental damage like premature ageing and dullness. Long term, it's clinically proven to improve skin texture and smoothness, short term, it made my skin feel lovely and soft, and look fresh and glowy.
The best for a boost: Lixir Night Swith PHA/AHA 10%
Lixir's PHA/AHA keeps things simple with a handful of key ingredients, making it easy to pinpoint any products you know aggravate your skin. This too, contains a mix of PHAs and AHAs (lactic acid), but rather than applying it neat to your face as you would with the others, it's best mixed into your moisturiser which dilutes it into a very comfortable, doable lotion that doesn't feel irritating on skin. Use it massaged across your face as and when you need an added boost of glow.
The best for hydrating: NeoStrata Bionic Lotion
Hands down, the gentlest offering of the bunch, this is ideal for sensitive skins who just want simple, straight-up formulas with no surprises. It applies like a light, fluid moisturiser and is made of 12 per cent Gluconolactone and three per cent lactobionic acid (both PHAs), which help to ever so gently keep cell turnover ticking by, as well as nourishing vitamin E. It's made by the same scientists behind Exuviance (above) and is steeped in research (it's clinically shown to improve the dryness, redness and flaking associated with eczema). It's no frills –the packaging is unspectacular, it's fragrance-free and it has a light, slippy cream-to-gel consistency, rather than anything particularly unctuous and luxurious. That said, it's the most comfortable face cream I've tried and one I would recommend to very sensitive skin types or anyone suffering from a skin flare-up. It definitely improved my skin texture (normally a bit dehydrated) and left my face feeling silky soft and radiant.
As with all exfoliators, use these alongside a good SPF.